The primary purpose of this research is to develop new knowledge regarding the pathophysiology of visual loss in glaucoma. There are two major approaches to this problem: 1. Information derived mainly from visual field examination, ophthalmoscopy, tonography, tonometry, and ophthalmodynanometry is compared with an analysis of high speed, high resolution fluorescein angiography in an effort to evaluate the vascular status of the optic nerve, choroid and retina; 2. Serial color photographs of the optic disc are analyzed and compared to data from opthalmoscopy and visual field examinations in an attempt to determine the feasibility of using disc photography as an additional means of following patients with or suspected of having glaucoma. To accomplish these purposes, patients with chronic open angle glaucoma, secondary types of glaucoma, and ocular hypertension have been and are being studied by the two approaches stated above. This primary goal has been and is being accompanied by efforts to perfect the research and photographic methods and to design a suitable statistical program to analyze the research data.